In alpine skiing, it is known that a boot is held on a ski by a front and a rear binding. To ensure that the ski is adapted to boots of different lengths, and also to allow unrestricted flection of the ski, one of the bindings, normally the rear binding, is longitudinally movable along a slide-rail.
Some bindings, in particular rental bindings, also incorporate a front binding that travels along a slide-rail fastened to the ski. This front binding can be placed in different longitudinal positions, thereby allowing adaptation to a wide range of boots of varying lengths.
Slide-rails allowing the longitudinal movement of a binding comprise a stationary part, or base, attached to the ski and a movable element which may, depending on the case, be a base plate on which the base of the binding is assembled, or else the base of the binding, which in this instance incorporates skids to provide for guidance of the body of the binding along the base.
Since the slide-rail comprises an element which moves in relation to a stationary element, the problem of the mechanical adjustment of these two components arises. If the component assembly is too tight, movement of the mobile element along the base proves difficult, thereby hindering adjustment of the longitudinal position of the bindings. In fact, the technician performing this adjustment must exert substantial force in order to move the binding. Furthermore, this movement will tend to occur jerkily and will require several successive back-and-forth motions to put the binding in its correct position. Adjustment procedures of this kind occur relatively frequently in rental skis. It will be easily understood that skiers will not appreciate a binding tightly adjusted in this manner. An excessively-tightened adjustment can also impair flection of the ski when this adjustment is localized between the rear binding and its slide-rail.
If, on the other hand, too much play is left between the two elements of the slide-rail when the boot is absent, the movable element can wobble in relation to the stationary part. This motion causes premature wear of the slide-rail, and, in the long run, deterioration of the binding operation. Moreover, it must be recognized that the skier does not find this motion pleasant, and that it impairs the accurate steering of the ski.
To solve this problem, the French Patent Application published under No. 2 646 093 proposes the insertion, between the two movable elements belonging to the slide-rail, of a layer of elastically-deformable and compressible material. However, the use of the device proves delicate.
Seen from another perspective, it may be recalled that some bindings are equipped with an interface plate located beneath the binding. The main role of this plate is to squeeze the threaded portion of the assembly screws in order to hold them in their holes ready to be screwed in place, until the binding is assembled to the ski. This plate is described, for example, in Japanese Patent Application No. 51-138 254, published under No. 53-65 130. However, there the role of the plate is limited to holding the screws in place, and the plate has no other function.